Bag-making machine

ABSTRACT

In a bag-making machine, a work unit such as a handle-applying station is independently displaceable in two directions perpendicular to one another and is driven by a drive shaft disposed at a fixed location, a propeller shaft having length compensating means connecting the drive shaft to a power input shaft for the work unit. Either the input shaft or the drive shaft is in the form of a centilever-mounted hollow shaft connected to the propeller shaft by a joint which is pivoted to an annular flange attached to the hollow shaft and which is also pivoted to a sleeve, the propeller shaft passing through the centrally free joint and through the hollow shaft, said sleeve making a positive rotary drive connection to the propeller shaft but being longitudinally displaceable thereon.

United States Patent 11 1 1111 3,859,894

Mundus Jan. 14, 1975 BAG-MAKING MACHINE 3,698,289 10/1972 Kamins et a1.93/35 H x 3,773,591 11/1973 Bla'r 93/35 H X [75] Inventor: s fi gLengemh of 3,810,811 5/1974 Bos se 93/35 11 x es p a1a, ermany [73]Assignee: Windmoller & Holscher, Lengerich im y Examiner-Roy Lake ofWestphalia, Germany Assistant ExaminerJames F. Coan Filed Nov 28 1973Attorney, Agent, or Firm-Fleit & Jacobson [21] App]. No.: 419,532 [57]ABSTRACT In a bag-making machine, a work unit such as a han- [30] F i Ali ti p i it D t die-applying station isdindtlapendentlydisplraltceablel in two directions perpen icu ar to one anot er an is Dl, 1972 ec Germany 2258925 dr1ven by a drive shaft d1sposed at a fixedlocat1on, a [52] Us. CL 93/8 W A 64/6 64/17 propeller shaft havinglength compensating means 4/23 93/8 connecting the drive shaft to apower input shaft for 51 1m. (:1 1331b 11/86 the Either the input Shaftthe drive shaft [58] Field of Search 93/35 H 8 WA 8 is in the form of acentilever-mounted hollow shaft 64/1C 6 connected to the propeller shaftby a joint which is pivoted to an annular flange attached to the hollow[56] References Cited shaft and which is also pivoted to a sleeve, thepropeller shaft passing through the centrally free joint and UNITEDSTATES PATENTS through the hollow shaft, said sleeve making a positiveWarper X rotary drive to propeller but 64/23 X being longitudinallydisplaceable thereon.

3,156,206 11/1964 Hall et al. 93/35 H X 1 Claim, 2 Drawing FiguresBAG-MAKING MACHINE The invention relates to a machine for making bags orsacks, particularly carrier bags, from heat-scalable material,comprising a work unit, for example a handleapplying station for thebags, which unit is independently displaceable in two directionsperpendicular to one another and is driven by a drive shaft disposed ata fixed location, a power input shaft for the work unit, and a propellershaft connecting said input and drive shafts by respective jointslocated adjacent the input and drive shafts, the propeller shaft beingprovided with length compensating means.

With such work units, and at least with handle-. applying stations forwelding injection-moulded handles to bag material, there is arequirement that the intervals between successive handles be veryaccurately set to a distance depending on the size of the bags beingmade. For example, it should be possible to set the centre line of thehandle-applying station at a very accurate distance from the centre lineof a welding bar which is located downstream thereof and serves to formthe side seams of the bags after the handles have been welded on. Moreparticularly, this spacing between the centre lines should be exactly 2%or 1% times the width of the bags being made (2 /2 times for narrow bagsand 1% times for wider bags). In order to suit all the possible settingsthat might be encountered in practice, it should therefore be possibleto adjust the work unit in the longitudinal direction of the machine bya distance equal to at least the width of the widest possiblebag size,for example 700 mm. Similar considerations apply to setting the workunit in a direction transversely of the machine. In this case, acharacteristic datum, for example the centre line of the welding jaw forthe handle in the case of a handleapplying station, must be at a veryspecial spacing from a fold line in the bag material, namely a distanceequal to the desired depth of the bags being made. Although it ispossible to set up the machine so that the fold line in the bagmateriial is spaced from the handle welding jaw of the handle-applyingstation by a distance exactly equal to the bag depth, the units forfolding the bag material are rigidly built into the machine whereas thedimensions of the bag material are likely to fluctuate. Thesefluctuations will result in fluctuations in the depths of the bags; theyoccur gradually rather than suddenly and can amount up to 2 cm. Althoughsuch a large variation in the depth of the bags is immaterial as far asthe bags are concerned, they must be taken into account during bagmanufacture by adjusting the spacing of the datum, i.e., the centre lineof the handle welding jaw, from the fold line of the bag material. If noadjustment were to be made, the handles would be welded on either toofar down the bag, in which case the upwardly projecting bag materialwould interfere with a good grip being obtained on the handles by theuser, or too high up the bag, in which case there might be insufficientbag material to which to weld the handles, or the handles might miss thebag material altogether. Accordingly, the fluctuations in the dimensionsof the bag material must be compensated by changing the transversepositions of the tools effecting the application of the handles.However, since the units for folding the bag material are rigidly buildinto the machine and not adjustable during operation, fluctuations inthe depth of the bags are compensated by adjusting the position of thehandleapplying station in a direction transversely of the machine. Tomake this possible, the mounting and the drive means for thehandle-applying station must be movable, in extreme cases up to about 50to mm.

It is known that a cardan shaft provided with length compensating meanscan be used to transmit mechanical power from a fixed point to one ofwhich the posi tion is variable in two directions. A. prerequisite forthis is that the extent of displacement of the movable point relativelyto the fixed point in a direction lengthwise of the cardan shaft beconsiderably smaller than the smallest possible distance between the twojoints of the cardan shaft or, when the movable point is closest to thefixed point, the two points be spaced apart at a distance larger thanthe smallest retracted length of the cardan shaft.

The aim of the invention is to provide a drive arrangement for theaforementioned case in which the movable point that is to be suppliedwith mechanical power moves within considerably larger limits than thosedetermined by the closest spacing of the movable point relatively to thefixed point, so that the bagmaking machine need not be unnecessarilylong, i.e., there can be a small spacing between the work unit and thedrive shaft.

According to the invention, a machine for making sacks or bags forheat-scalable material comprises a work unit which is independentlydisplaceable in two directions perpendicular to one another and isdriven by a drive shaft disposed at a fixed location, a power inputshaft for the work unit, and a propeller shaft connecting said input anddrive shafts by respective joints located adjacent the input and driveshafts, the propel.- ler shaft being provided with length compensatingmeans, wherein the input shaft or the drive shaft is in the form of acantilever-mounted hollow shaft and the associated joint is a centrallyfree joint comprising a ring, particularly the pivot ring of a universaljoint, which ring is pivoted to an annular flange attached to the hollowshaft and which is also pivoted to a sleeve, said propeller shaftpassing through the centrally free joint and through the hollow shaft,said sleeve making a positive rotary drive connection to the propellershaft but being longitudinally displaceable thereon.

In this way, the central portion of the propeller shaft, which may besplined, may be as long as required (within the limits set by anyproblems that may arise through oscillations) and its entire length maybe utilized for displacing the movable point. More particularly, themovable point can be brought very close to the fixed point of the powersupply. Although particular reference has been made to the use of acardan shaft for the propeller shaft, the advantages of the inventioncan also be obtained with other types of propeller shafts, particularlythose having homokinetic joints or joints using fixedly screwed rubberor resilient transmission elements.

An example of the invention will now be described with reference to theaccompanying drawings, wherein:

FIG, 1 is a diagrammatic fragmentary plan view of a bagmaking machine,and

FIG. 2 is an enlarged sectional view of the portion encircled at A inFIG. 1.

Referring to FIG. I, a drive motor 1 operates through gearing 2 to turna drive shaft 3 which is at a fixed location. The drive shaft 3terminates at a power supply point 4 comprising a universal joint 5. Thekinematic point of the universal joint 5 is designated 6. At thiskinematic point, the longitudinal centre line of the drive shaft 3intersects that of a propeller shaft 7 of which substantially all thecentral portion is provided with a splined profile. A welding bar 9having a longitudinal centre line 10 serves to apply transverse weldseams to bag material 19 which is fed in the direction of the arrow aand comprises a two-ply web containing fold lines adjacent the edge 18.A handle-applying station 11 having a longitudinal centre line 14 isoperated in synchronism with the machine cycle to weld handles atpredetermined intervals to the web 19. For this purpose, thehandle-applying station comprises a welding jaw 12 which has alongitudinal centre line 13 and is reciprocatable in the direction ofthe arrow a and back again in synchronism with the machine cycle. Thetransverse centre line of the welding jaw 12 coincides with thelongitudinal centre line 14 of the handleapplying station. The latterincludes a hopper 34 for injection-moulded handles.

The handle-applying station 11 is displaceable, as shown in brokenlines, in a direction parallel to the web movement a through a distanceL and, independently thereof, in a transverse direction through thedistance Q. Within the station 11 there is a universal joint having akinematic point 15 and to be described more fully hereinafter. From aconstructional point of view, the inclination of the central portion 7of the propeller shaft relatively to the drive shaft 3 and a power inputshaft 21 (FIG. 2) of the station 11 is limited between the positionsshown at 16 and 17 in chain-dotted lines in FIG. 1. Accordingly, thestation 11 is not freely displaceable within a rectangle having thedimensions Q and L but within a hexagon that is shown by thecrosshatching in FIG. 1. In the illustrated example, the transversecentre line 14 of the welding jaw 12 of the handle-applying station isset to a spacing D from the centre line 10 of the welding bar 9, thisspacing being equal to 1 /2 times the width B of the carrier bags to bemade. The longitudinal centre line 13 of the jaw 12 is set at a spacingT from the lower folded edge 18 of the web 19 equal to the desired depthof the bags to be made. Since the width of the web 19, and thus thedepth of the bags made therefrom, can fluctuate within wide limits butthe position of the base fold line 18 is fixed once the machine has beenset up, any fluctuation can be com pensated only by changing thetransverse position of the station 11 with a view to keeping a constantspacing S between the top edges of the web 19 and a weld seam by whichthe handles are secured to the web 19.

The displaceability of the handle-applying station in two direction andindependently of one another, and the close proximity of the station 11to the stationary point 4 of power supply, are obtainable with the aidof the propeller shaft and universal joint as illustrated in FIG. 2. InFIG. 2, a wall 20 of the handle-applying station is cast in one piecewith a bearing sleeve which permits cantilever mounting of theaforementioned input shaft 21, which is hollow. Although the shaft 21 isquite short, roller bearings are used to support only its right-handend. On the left-hand side, the shaft 21 carries a pinion 23 whichengages a drive gear 24 of the handle-applying station. The input shaft21 is connected to the central portion 7 of the propeller shaft by auniversal joint 25 having the aforementioned kinematic point 15. Byreason of the splines on the propeller shaft, the shaft 21 is inpositive drive connection therewith but axially displaceable relativelythereto. The universal joint 25 is centrally free, i.e., a shaft may bepushed through the centre of the joint. This central freedom is obtainedby means of a pivot ring 26 carrying four radially inwardly projectingpivots 27 which are equally spaced circumferentially of the ring. Theupper half of the joint 25 shown in cross-section in FIG. 2 should beimagined as being turned through relatively to the lower half. Each pairof opposed pivots 27 provides a pivotal connection to a respectivebifurcated member 28 or 29 containing complementary bearing sleeves. Oneof the bifurcated members by a sleeve 30 which is axially displaceableon the central portion 7 of the propeller shaft and the other bifurcatedmember (29) is connected to the power input shaft 21 by means of anannular flange 31. The sleeve 30 is displaceable along the propellershaft within very wide limits determined by the unsupported length ofthe propeller shaft portion 7 (which could give rise to oscillations athigh speeds). To protect the interior from dirt and foreign matter, thebearing sleeve on the wall 20 is connected to a bellows-like cover 32which carries a sealing ring 33 for engaging the splines of thepropeller shaft but permitting rotation of the shaft relatively to thecover.

Apart from the aforementioned use of a centrally free universal joint,other basic constructions may be employed. It should also be mentionedthat the power input is carried 21 and universal joint 25 need not justbe provided on the wall of the handle-applying station facing theupstream direction but could also be provided on the downstream wall.Further, the bifurcated members free universal joint need not bedisposed on the left-hand side of the input shaft 21 as illustrated butcould be on the right-hand side. Still further, the universal joint 25could, instead of being associated with the input shaft 21, be providedfor the drive shaft 3.

I claim:

1. A machine for making sacks or bags from heatsealable material,comprising a work unit which is independently displaceable in twodirections perpendicular to one another and is driven by a drive shaftdisposed at a fixed location, a power input shaft for the work unit, anda propeller shaft connecting said input and drive shafts by respectivejoints located adjacent the input and drive shafts, the propeller shaftbeing provided with length compensating means, wherein the input shaftor the drive shaft is in the form of a cantilever-mounted hollow shaftand the associated joint is a centrally free joint comprising a ringwhich is pivoted to an annular flange attached to the hollow shaft andwhich is also pivoted to a sleeve, said propeller shaft passing throughthe centrally free joint and through the hollow shaft, said sleevemaking a positive rotary drive connection to the propeller shaft butbeing longitudinally displaceable thereon.

1. A machine for making sacks or bags from heat-sealable material,comprising a work unit which is independently displaceable in twodirections perpendicular to one another and is driven by a drive shaftdisposed at a fixed location, a power input shaft for the work unit, anda propeller shaft connecting said input and drive shafts by respectivejoints located adjacent the input and drive shafts, the propeller shaftbeing provided with length compensating means, wherein the input shaftor the drive shaft is in the form of a cantilever-mounted hollow shaftand the associated joint is a centrally free joint comprising a ringwhich is pivoted to an annular flange attached to the hollow shaft andwhich is also pivoted to a sleeve, said propeller shaft passing throughthe centrally free joint and through the hollow shaft, said sleevemaking a positive rotary drive connection to the propeller shaft butbeing longitudinally displaceable thereon.